Control system for equipment on a vehicle with a hybrid-electric powertrain

ABSTRACT

A power take off system for a hybrid-electric vehicle comprises an internal combustion engine, a hybrid-electric motor and generator, a power take off mechanism, a control module, and an engaging mechanism. The motor and generator couples to the internal combustion engine. The power take off mechanism couples to the internal combustion engine and the motor and generator. The power take off mechanism receives torque from at least one of the engine and the motor and generator. The control module is disposed in electrical communication with a system controller. The control module generates output signals for controlling the engine. The engaging mechanism is disposed in electrical communication with the system controller. The engaging mechanism has a first mode and a second mode. The power take off mechanism is decoupled from the engine and the motor and generator in response to an output signal generated by the system controller.

RELATED APPLICATIONS

The present application claims priority to U.S. Provisional PatentApplication No. 61/113,702 filed on Nov. 12, 2008, which is hereinincorporated by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates to a hydraulic load control system forpower take off (“PTO”) equipment on a vehicle with a hybrid-electricpowertrain, and more particularly to a system and method fortransitioning between internal combustion engine powered operation ofthe PTO and hybrid-electric powertrain powered operation of the PTO thatsupplies power for the hydraulic load.

BACKGROUND

Many vehicles now utilize hybrid-electric powertrains in order toincrease the efficiency of the vehicle. A hybrid-electric powertraintypically involves an internal combustion engine that operates agenerator that produces electrical power that may be used to driveelectric motors used to move the vehicle. The electric motors may beused to provide power to wheels of the vehicle to move the vehicle, orthe electric motors may be used to supplement power provided to thewheels by the internal combustion engine and a transmission. In certainoperational situations, the electric motors may supply all of the powerto the wheels, such as under low speed operations. In addition toproviding power to move the vehicle, the hybrid-electric powertrain maybe used to power a PTO of the vehicle, sometimes also referred to as anelectric PTO or EPTO when powered by a hybrid-electric powertrain, thatin turn powers PTO driven accessories.

In some vehicles, such as utility trucks, for example, a PTO may be usedto drive a hydraulic pump for an on-board vehicle hydraulic system. Insome configurations, a PTO driven accessory may be powered while thevehicle is moving. In other configurations, a PTO driven accessory maybe powered while the vehicle is stationary and the vehicle is beingpowered by the internal combustion engine. Still others may be drivenwhile the vehicle is either stationary or traveling. Controlarrangements are provided for the operator for any type of PTOconfiguration.

In some PTO applications the vehicle's particular internal combustionengine may be of a capacity that makes it inefficient as a source ofmotive power for the PTO application due to the relatively low powerdemands, or intermittent operation, of the PTO application. Under suchcircumstances the hybrid-electric powertrain may power the PTO, that is,use of the electric motor and generator instead of the IC engine tosupport mechanical PTO, may be employed. Where power demands are low,the electric motor and generator will typically exhibit relatively lowparasitic losses compared to an internal combustion engine. Where powerdemand is intermittent, but a quick response is provided, the electricmotor and generator provides such availability without incurring theidling losses of an internal combustion engine.

Conventionally, once a hybrid electric vehicle equipped for EPTO entersthe EPTO operational mode, the electric motor and generator remainsunpowered until an active input or power demand signal is provided.Typically, the power demand signal results from an operator inputreceived through a body mounted switch which is part of data linkmodule. Such a module could be the remote power module described in U.S.Pat. No. 6,272,402 to Kelwaski, the entire disclosure of which isincorporated herein by this reference. The switch passes the powerdemand signal over a data bus such as a Controller Area Network (CAN)now commonly used to integrate vehicle control functions.

A power demand signal for operation of the traction motor is only one ofthe possible inputs that could occur and which could be received by atraction motor controller connected to the controller area network ofthe vehicle. Due to the type, number and complexities of the possibleinputs that can be supplied from a data link module added by a truckequipment manufacturer (TEM), as well as from other sources, issues mayarise regarding adequate control of the electric motor and generator,particularly during the initial phases of a product's introduction, orduring field maintenance, especially if the vehicle has been subject tooperator modification or has been damaged. As a result the tractionmotor may not operate as expected. In introducing a product, a TEM canfind itself in a situation where the data link module cannot provideaccurate power demand requests for electric motor and generatoroperation for EPTO operation due to programming problems, interactionwith other vehicle programming, or other architectural problems.

A hybrid-electric powertrain may solely power the PTO of the vehiclewhen the PTO is operating a PTO driven accessory adapted to only beutilized by a stopped vehicle, such as lift attachment, or a diggingattachment. In some situations, the hybrid-electric powertrain is notcapable of providing sufficient power to the PTO, and thus, the PTOneeds to be powered by the internal combustion engine. In othersituations, batteries of the hybrid-electric powertrain may need to berecharged. In both of these situations, if the PTO is being powered bythe hybrid-electric powertrain, the PTO must be stopped, such that theinternal combustion engine may be started to deliver power to the PTO,or to recharge batteries of the hybrid-electric powertrain. Therefore, aneed exists for a system and method that is capable of shutting down aPTO that is being driven by a hybrid-electric powertrain, such that aninternal combustion engine may be started to power the PTO, or torecharge batteries of the hybrid-electric powertrain.

SUMMARY

According to one embodiment, a vehicle equipped for power take offoperation using direct application of power from a hybrid electricpowertrain comprises a controller are network, a data link, andprogramming. The controller area network and body computer are connectedto receive a plurality of chassis input signals. The data link basedremote power module is installed on the vehicle and generates bodydemand signals for initiating operation of the vehicle hybrid electricpowertrain for a power take off operation. The programming is forexecution by the body computer in response to selected chassis inputsignals for generating control signals for the hybrid electricpowertrain for the power take off operation.

According to another embodiment, a vehicle equipped for power take offoperation using direct application of power from a hybrid electricpowertrain, comprises means responsive to a plurality of chassis inputsignals for generating a chassis demand signal for initiating operationof the hybrid electric powertrain to support power take off operation.The vehicle additionally comprises means responsive to operator inputsand installed on the vehicle for generating body demand signals forinitiating operation of the hybrid electric powertrain to support powertake off operation.

According to a further embodiment, a vehicle comprises an internalcombustion engine and an electric motor and generator, a body computer,a data link based module, and an execution module. The internalcombustion engine and the electric motor and generator are connectableusing an autoclutch to allow parallel operation for power take offoperation. The body computer connects to a plurality of chassis inputsand receives input therefrom, and processes programming using values forthe chassis inputs to generate control signals. The data link basedmodule is installed on the vehicle through which inputs can be enteredby an operator to initiate operation of the power take off operationusing either the internal combustion engine or the electric motor andgenerator. The execution module is stored on a memory in the bodycomputer and overrides the data link based module for initiatingoperation of at least one of the internal combustion engine and theelectric motor and generator for power take off operation with theplurality of chassis inputs.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevation of a vehicle equipped for a power take-offoperation.

FIG. 2 is a high level block diagram of a control system for the vehicleof FIG. 1.

FIG. 3 is a diagram for a state machine relating to a power take-offoperation which can be implemented on the control system of FIG. 2.

FIGS. 4A-D are schematic illustrations of a hybrid powertrain applied tosupport a power take-off operation.

FIG. 5 is a system diagram for chassis and body initiated hybridelectric motor and generator control for power take-off operation.

FIG. 6 is a map of input and output pin connections for a remote powermodule in the system diagram of FIG. 5.

FIG. 7 is a map of input and output locations for the electrical systemcontroller of FIG. 5.

FIG. 8 is a schematic view of a vehicle having a hybrid-electricpowertrain with a PTO driven hydraulic system.

FIG. 9 is a system diagram for a control system of the vehicle of FIG.8;

FIG. 10 is a schematic view of a vehicle having a hybrid-electricpowertrain with a PTO driven hydraulic system having an accumulator andan accumulator isolation valve.

DETAILED DESCRIPTION

Referring now to the figures and in particular to FIG. 1, a hybridmobile aerial lift truck 1 is illustrated. Hybrid mobile aerial lifttruck 1 serves as an example of a medium duty vehicle which supports aPTO vocation, or an EPTO vocation. It is to be noted that embodimentsdescribed herein, possibly with appropriate modifications, may be usedwith any suitable vehicle. Additional information regarding hybridpowertrains may be found in U.S. Pat. No. 7,281,595 entitled “System ForIntegrating Body Equipment With a Vehicle Hybrid Powertrain,” which isassigned to the assignee of the present application and which is fullyincorporated herein by reference.

The mobile aerial lift truck 1 includes a PTO load, here an aerial liftunit 2 mounted to a bed on a back portion of the truck 1. Duringconfiguration for EPTO operation, the transmission for mobile aeriallift truck 1 may be placed in park, the park brake may be set,outriggers may be deployed to stabilize the vehicle, and indication froman onboard network that vehicle speed is less than 5 kph may be receivedbefore the vehicle enters PTO mode. For other types of vehiclesdifferent indications may indicate readiness for PTO operation, whichmay or may not involve stopping the vehicle.

The aerial lift unit 2 includes a lower boom 3 and an upper boom 4pivotally connected to each other. The lower boom 3 is in turn mountedto rotate on the truck bed on a support 6 and rotatable support bracket7. The rotatable support bracket 7 includes a pivoting mount 8 for oneend of lower boom 3. A bucket 5 is secured to the free end of upper boom4 and supports personnel during lifting of the bucket to and support ofthe bucket within a work area. Bucket 5 is pivotally attached to thefree end of boom 4 to maintain a horizontal orientation. A lifting unit9 is connected between bracket 7 and the lower boom 3. A pivotconnection 10 connects the lower boom cylinder 11 of unit 9 to thebracket 7. A cylinder rod 12 extends from the cylinder 11 and ispivotally connected to the boom 3 through a pivot 13. Lower boomcylinder unit 9 is connected to a pressurized supply of a suitablehydraulic fluid, which allows the assembly to be lifted and lowered. Asource of pressurized hydraulic fluid may be an automatic transmissionor a separate pump. The outer end of the lower boom 3 is connected tothe lower and pivot end of the upper boom 4. A pivot 16 interconnectsthe outer end of the lower boom 3 to the pivot end of the upper boom 4.An upper boom compensating cylinder unit or assembly 17 is connectedbetween the lower boom 3 and the upper boom 4 for moving the upper boomabout pivot 16 to position the upper boom relative to the lower boom 3.The upper-boom, compensating cylinder unit 17 allows independentmovement of the upper boom 4 relative to lower boom 3 and providescompensating motion between the booms to raise the upper boom with thelower boom. Unit 17 is supplied with pressurized hydraulic fluid fromthe same source as unit 9.

Referring to FIG. 2, a high level schematic of a control system 21representative of a system usable with vehicle 1 control is illustrated.An electrical system controller 24, a type of a body computer, is linkedby a public datalink 18 (here illustrated as a SAE compliant J1939 CANbus) to a variety of local controllers which in turn implement directcontrol over most vehicle 1 functions. Electrical system controller(“ESC”) 24 may also be directly connected to selected inputs and outputsand other busses. Direct “chassis inputs” include, an ignition switchinput, a brake pedal position input, a hood position input and a parkbrake position sensor, which are connected to supply signals to the ESC24. Other inputs to ESC 24 may exist. Signals for PTO operationalcontrol from within a cab may be implemented using an in-cab switchpack(s) 56. In-cab switch pack 56 is connected to ESC 24 over aproprietary data link 64 conforming to the SAE J1708 standard. Data link64 is a low baud rate data connection, typically on the order of 9.7Kbaud. Five controllers in addition to the ESC 24 are illustratedconnected to the public datalink 18. These controllers are the enginecontroller (“ECM”) 46, the transmission controller 42, a gauge clustercontroller 58, a hybrid controller 48 and an antilock brake systemcontroller (“ABS”) 50. Other controllers may exist on a given vehicle.Datalink 18 is the bus for a public controller area network (“CAN”)conforming to the SAE J1939 standard and under current practice supportsdata transmission at up to 250 Kbaud. It will be understood that othercontrollers may be installed on the vehicle 1 in communication withdatalink 18. ABS controller 50, as is conventional, controls applicationof brakes 52 and receives wheel speed sensor signals from sensors 54.Wheel speed is reported over datalink 18 and is monitored bytransmission controller 42.

Vehicle 1 is illustrated as a parallel hybrid electric vehicle whichutilizes a powertrain 20 in which the output of either an internalcombustion engine 28, an electric motor and generator 32, or both, maybe coupled to the drive wheels 26. Internal combustion engine 28 may bea diesel engine. As with other full hybrid systems, the system isintended to recapture the vehicle's inertial momentum during braking orslowing. The electric motor and generator 32 is run as a generator fromthe wheels, and the generated electricity is stored in batteries duringbraking or slowing. Later the stored electrical power can be used to runthe electric motor and generator 32 instead of or to supplement theinternal combustion engine 28 to extend the range of the vehicle'sconventional fuel supply. Powertrain 20 is a particular variation ofhybrid design which provides support for PTO either from internalcombustion engine 28 or from the electric motor and generator 32. Whenthe internal combustion engine 28 is used for PTO it can be run at anefficient power output level and used to concurrently support of PTOoperation and to run the electric motor and generator 32 in itsgenerator mode to recharge the traction batteries 34. Usually a PTOapplication consumes less power than power output at a thermallyefficient internal combustion engine 28 throttle setting.

The electric motor and generator 32 is used to recapture the vehicle'skinetic energy during deceleration by using the drive wheels 26 to drivethe electric motor and generator 32. At such times auto-clutch 30disconnects the engine 28 from the electric motor and generator 32.Engine 28 may be utilized to supply power to both generate electricityand operate PTO system 22, to provide motive power to drive wheels 26,or to provide motive power and to run a generator to generateelectricity. Where the PTO system 22 is an aerial lift unit 2 it isunlikely that it would be operated when the vehicle was in motion, andthe description here assumes that in fact that the vehicle will bestopped for EPTO, but other PTO applications may exist where this is notdone.

Powertrain 20 provides for the recapture of kinetic energy in responseto the electric motor and generator 32 being back driven by thevehicle's kinetic force. The transitions between positive and negativetraction motor contribution are detected and managed by a hybridcontroller 48. Electric motor and generator 32, during braking,generates electricity which is applied to traction batteries 34 throughinverter 36. Hybrid controller 48 looks at the ABS controller 50datalink traffic to determine if regenerative kinetic braking wouldincrease or enhance a wheel slippage condition if regenerative brakingwere initiated. Transmission controller 42 detects related data trafficon datalink 18 and translates these data as control signals forapplication to hybrid controller 48 over datalink 68. Electric motor andgenerator 32, during braking, generates electricity which is applied tothe traction batteries 34 through hybrid inverter 36. Some electricalpower may be diverted from hybrid inverter to maintain the charge of aconventional 12-volt DC Chassis battery 60 through a voltage step downDC/DC inverter 62.

Traction batteries may be the only electrical power storage system forvehicle 1. In vehicles contemporary to the writing of this applicationnumerous 12 volt applications remain in common use and vehicle 1 may beequipped with a parallel 12 volt system to support the vehicle. Thispossible parallel system is not shown for the sake of simplicity ofillustration. Inclusion of such a parallel system would allow the use ofreadily available and inexpensive components designed for motor vehicleuse, such as incandescent bulbs for illumination. However, using 12 voltcomponents may incur a vehicle weight penalty and involve extracomplexity.

Electric motor and generator 32 may be used to propel vehicle 1 bydrawing power from battery 34 through inverter 36, which supplies 3phase 340 volt rms power. Battery 34 is sometimes referred to as thetraction battery to distinguish it from a secondary 12 volt lead acidbattery 60 used to supply power to various vehicle systems. However,high mass utility vehicles tend to exhibit far poorer gains from hybridlocomotion than do automobiles. Thus stored electrical power is alsoused to power the EPTO system 22. In addition, electric motor andgenerator 32 is used for starting engine 28 when the ignition is in thestart position. Under some circumstances engine 28 is used to drive theelectric motor and generator 32 with the transmission 38 in a neutralstate to generate electricity for recharging battery 34 and/or engagedto the PTO system 22 to generate electricity for recharging the battery34 and operate the PTO system 22. This would occur in response to heavyPTO system 22 use which draws down the charge on battery 34. Typicallyengine 28 has a far greater output capacity than is used for operatingPTO system 22. As a result, using it to directly run PTO system 22 fulltime would be highly inefficient due to parasitic losses incurred in theengine or idling losses which would occur if operation wereintermittent. Greater efficiency is obtained by running engine 22 atclose to its rated output to recharge battery 34 and provide power tothe PTO, and then shutting down the engine and using battery 34 tosupply electricity to electric motor and generator 32 to operate PTOsystem 22.

An aerial lift unit 2 is an example of a system which may be used onlysporadically by a worker first to raise and later to reposition itsbasket 5. Operating the aerial lift unit 2 using the traction motor 32avoids idling of engine 28. Engine 28 runs periodically at an efficientspeed to recharge the battery if battery 34 is in a state of relativedischarge. Battery 34 state of charge is determined by the hybridcontroller 48, which passes this information to transmission controller42 over datalink 68. Transmission controller 42 can in turn can requestESC 24 to engage engine 28 by a message to the ESC 24, which in turnsends engine operation requests (i.e. engine start and stop signals) toECM 46. The availability of engine 28 may depend on certain programmed(or hardwired) interlocks, such as hood position.

Powertrain 20 comprises an engine 28 connected in line with an autoclutch 30 which allows disconnection of the engine 28 from the rest ofthe powertrain when the engine is not being used for motive power or forrecharging battery 34. Auto clutch 30 is directly coupled to theelectric motor and generator 32 which in turn is connected to atransmission 38. Transmission 38 is in turn used to apply power from theelectric motor and generator 32 to either the PTO system 22 or to drivewheels 26. Transmission 38 is bi-directional and can be used to transmitenergy from the drive wheels 26 back to the electric motor and generator32. Electric motor and generator 32 may be used to provide motive energy(either alone or in cooperation with the engine 28) to transmission 38.When used as a generator the electric motor and generator supplieselectricity to inverter 36 which supplies direct current for rechargingbattery 34.

A control system 21 implements cooperation of the control elements forthe operations just described. ESC 24 receives inputs relating tothrottle position, brake pedal position, ignition state and PTO inputsfrom a user and passes these to the transmission controller 42 which inturn passes the signals to the hybrid controller 48. Hybrid controller48 determines, based on available battery charge state, whether theinternal combustion engine 28 or the traction motor 32 satisfiesrequests for power. Hybrid controller 48 with ESC 24 generates theappropriate signals for application to datalink 18 for instructing theECM 46 to turn engine 28 on and off and, if on, at what power output tooperate the engine. Transmission controller 42 controls engagement ofauto clutch 30. Transmission controller 42 further controls the state oftransmission 38 in response to transmission push button controller 72,determining the gear the transmission is in or if the transmission is todeliver drive torque to the drive wheels 26 or to a hydraulic pump whichis part of PTO system 22 (or simply pressurized hydraulic fluid to PTOsystem 22 where transmission 38 serves as the hydraulic pump) or if thetransmission is to be in neutral. For purposes of illustration only, avehicle may come equipped with more than one PTO system, and a secondarypneumatic system using a multi-solenoid valve assembly 85 and pneumaticPTO device 87 is shown under the direct control of ESC 24.

PTO 22 control is conventionally implemented through one or more remotepower modules (RPMs). Remote power modules are data-linked expansioninput/output modules dedicated to the ESC 24, which is programmed toutilize them. Where RPMs 40 function as the PTO controller they can beconfigured to provide hardwire outputs 70 and hardwire inputs used bythe PTO device 22 and to and from the load/aerial lift unit 2. Requestsfor movement from the aerial lift unit 2 and position reports areapplied to the proprietary datalink 74 for transmission to the ESC 24,which translates them into specific requests for the other controllers,e.g. a request for PTO power. ESC 24 is also programmed to control valvestates through RPMs 40 in PTO device 22. Remote power modules are morefully described in U.S. Pat. No. 6,272,402, which is assigned to theassignee of the present application and which is fully incorporatedherein by reference. At the time the '402 patent was written what arenow termed “Remote Power Modules” were called “Remote InterfaceModules”. It is contemplated that the TEMs who provide the PTO vocationwill order or equip a vehicle with RPMs 40 to support the PTO and supplya switch pack 57 for connection to the RPM 40. TEMs are colloquiallyknown as “body builders” and signals from an RPM 40 provided for bodybuilder supplied vehicle vocations are termed “body power demandsignals”.

Body power demand signals may be subject to corruption, vehicle damageor architectural conflicts over the vehicle controller area network.Accordingly an alternative mechanism is provided to generate powerdemand signals for the PTO from the vehicle's conventional controlnetwork. A way of providing for operator initiation of such a powerdemand signal without use of RPM 40 is to use the vehicle's conventionalcontrols including controls which give rise to what are termed “chassisinputs”. Power demand signals for PTO operation originating from suchalternative mechanisms are termed “chassis power demand signals”. Anexample of such could be flashing the headlamps twice while applying theparking brake, or some other easy to remember, but seeminglyidiosyncratic control usage, so long as the control choice does notinvolve the PTO dedicated RPM 40.

Transmission controller and ESC 24 both operate as portals and/ortranslation devices between the various datalinks. Proprietary datalinks68 and 74 operate at substantially higher baud rates than does thepublic datalink 18, and accordingly, buffering is provided for a messagepassed from one link to another. Additionally, a message may bereformatted, or a message on one link may be changed to another type ofmessage on the second link, e.g. a movement request over datalink 74 maytranslate to a request for transmission engagement from ESC 24 totransmission controller 42. Datalinks 18, 68 and 74 are all controllerarea networks and conform to the SAE J1939 protocol. Datalink 64conforms to the SAE J1708 protocol.

Referring to FIG. 3 a representative state machine 300 is used toillustrate one possible control regime. State machine 300 is enteredthrough either of two EPTO enabled states 300, 302, depending uponwhether engine 28 is operating to recharge the traction batteries 34 ornot. In the EPTO enabled state the conditions triggering EPTO operationhave been met, but the actual PTO vocation is not powered. Dependingupon the state of charge of the traction batteries 34, engine 28 may beoperating (state 302) or may not be running (state 304). In any statewhere the engine 28 is on the auto clutch 30 is engaged (+). The stateof charge which initiates battery charging is less than the state ofcharge at which charging is discontinued to prevent frequent cycling ofthe engine 28 on and off. The EPTO enabled states (302, 304) providethat the transmission 38 is disengaged. In state 302 where batteries 34are being charged, the electric motor and generator 32 is in itsgenerator mode. In state 304 where batteries 34 are considered charged,the state of the electric motor and generator 32 need not be defined andmay be left in its prior state.

Four EPTO operating states, 306, 308, 310 and 312 are defined. Thesestates occur in response to either a body power demand or chassis powerdemand. Within PTO vehicle battery charging continues to function. State306 provides that the engine 28 be on, the auto clutch 30 be engaged,the electric motor and generator 32 be in its generator mode and thetransmission be in gear for PTO. In state 308 the engine 28 is off, theauto clutch 30 is disengaged, the traction motor is in its motor modeand running and the transmission 38 be in gear for PTO. States 306 and308, as a class, are exited upon loss of the body power demand signal(which may occur as a result of cancellation of PTO enable) or upon oroccurrence of a chassis power demand signal. Changes in state stemmingfrom the battery state of charge can force changes within the classbetween states 306 and 308. EPTO operating states 310 and 312 areidentical to states 306 and 308, respectively, except that loss of thebody power demand signal does not result in one of states 310, 312 beingexited. Only loss of the chassis power demand signal results in exitfrom EPTO operating states 310 or 312, taken as a class, althoughtransitions within the class (i.e. between 310 and 312) can result fromthe battery state of charge. Upon loss of a chassis power demand signalthe exit route from states 310, 312, depends upon whether a body powerdemand signal is present. If it is the operational state moves fromstates 310 or 312 to states 306 or 308, respectively. If it is not, thento states 302 or 304. If the body power demand signal was lost due toexit from the EPTO enable conditions than states 302 or 304 are exitedalong the “OFF” routes. For transitions within a class, particularlyfrom an engine 28 off to an engine 28 on state, an intermediary statemay be provided where the auto-clutch 30 is engaged to permit thetraction motor to crank the engine.

FIGS. 4A-D illustrate graphically what occurs on the vehicle in thevarious states of the state machine implemented through appropriateprogramming of the ESC 24. FIG. 4A corresponds to state 304, one of theEPTO enabled state. FIG. 4B corresponds to state 302, the other EPTOenabled state. FIG. 4C corresponds to states 308 and 312, while FIG. 4Dcorresponds to states 306 and 310. In FIG. 4A the IC engine 28 is off(state 100), the auto clutch is disengaged (state 102), the electricmotor and generator 32 state may be undefined, but is shown as beingmotor mode (104). With electric motor and generator 32 in the motor modethe battery is shown in a discharge ready state 108. The transmission isshown as in gear (106), though this is elective. In FIG. 4B batterycharging 128 is occurring as a result of the IC engine running 120, theauto clutch being engaged 122 with engine torque being applied throughthe auto clutch to the electric motor and generator 32 operating in itsgenerator mode 124. The transmission is out of gear 126.

FIG. 4C corresponds to state machine 300 states 308 and 312 with theengine 28 being off 100, the auto clutch 30 being disengaged 102. Thebattery 34 is discharging 108 to operate the traction motor in itsrunning state 104 to apply torque to the transmission 38 which is ingear 126 to apply drive torque to the PTO. FIG. 4D corresponds to statemachine 300 states 306 and 310. The IC engine 28 is running 120 tosupply power through an engaged 122 auto clutch to operate the electricmotor and generator 32 in it generator mode to supply electrical powerto a charging (128) battery and to supply torque through thetransmission to the PTO application.

FIGS. 5-7 illustrate a specific control arrangement and networkarchitecture on which the state machine 300 may be implemented.Additional information regarding control systems for hybrid powertrainsmay be found in U.S. patent application Ser. No. 12/239,885 filed onSep. 29, 2008 and entitled “Hybrid Electric Vehicle Traction MotorDriven Power take off Control System” which is assigned to the assigneeof the present application and which is fully incorporated herein byreference, as well as U.S. patent application Ser. No. 12/508,737 filedon Jul. 24, 2009, which is assigned to the assignee of the presentapplication and which is fully incorporated herein by reference. Thearrangement also provides control over a secondary pneumatic powertake-off operation 87 to illustrate that conventional PTO may be mixedwith EPTO on a vehicle. Electrical system controller 24 controls thesecondary pneumatic PTO 87 using a multiple solenoid valve assembly 85.Available air pressure may dictate control responses and accordingly anair pressure transducer 99 is connected to provide air pressure readingsdirectly as inputs to the electrical system controller 24.Alternatively, EPTO could be implemented using the pneumatic system ifthe traction motor PTO were an air pump.

The J1939 compliant cable 74 connecting ESC 24 to RPM 40 is a twistedpair of cables. RPM 40 is shown with 6 hardwire inputs (A-F) and oneoutput. A twisted pair cable 64 conforming to the SAE J1708 standardconnects ESC 24 to a inlay 64 for the cab dash panel on which variouscontrol switches are mounted. The public J1939 twisted pair cable 18connects ESC 24 to the gauge controller 58, the hybrid controller 48 andthe transmission controller 42. The transmission controller 42 isprovided with a private connection to the cab mounted transmissioncontrol console 72. A connection between the hybrid controller 48 andthe console 72 is omitted in this configuration though it may beprovided in some contexts.

FIG. 6 illustrates in detail the input and output pin usage for RPM 40for a specific application. Input pin A is the Hybrid Electric Vehicledemand circuit 1 input which can be a 12 volt DC or ground signal. Whenactive the traction motor runs continuously. Input pin B is the HybridElectric Vehicle demand circuit 2 input which can be a 12 volt DC orground signal. When active, the traction motor runs continuously. Inputpin C is the Hybrid Electric Vehicle demand circuit 3 input which can bea 12 volt DC or ground signal. When the signal is active the tractionmotor runs continuously. Input pin D is the Hybrid Electric Vehicledemand circuit 4 input which can be a 12 volt DC or ground signal. Whenthe signal is active the traction motor runs continuously. In otherwords the designer can provide four remote locations for switches fromwhich an operator can initiate a PTO body power demand signal to operatethe traction motor. Input pin E is a hybrid electric vehicle remote PTOdisable input. The signal can be either 12 volts DC or ground. Whenactive PTO is disabled. Input pin F is the hybrid electric vehicle EPTOengaged feedback signal. This signal is a ground signal originating witha PTO mounted pressure or ball detent feedback switch. The output pincarries the actual power demand signal. As noted this may be subject tovarious interlocks. In the example the interlock conditions are thatmeasured vehicle speed be less than 3 miles per hour, the gear settingbe neutral and the park brake set.

FIG. 7 illustrates the location of chassis output pins and chassis inputpins on the electrical system controller 24.

The system described here provides a secondary mechanism for controllingthe hybrid electric motor and generator through the use of variousoriginal equipment manufacturer (OEM) chassis inputs, circumventing theTEMs' input (demand) signal sourcing devices (e.g. the RPM 40).Initiating this mode of operation can be made as simple as desired byuse of a single in-cab mounted switch, which may be located in theswitch pack 56, or which may be made more complex and less obvious byusing a sequence of control inputs to operate as a “code”. For example,with the vehicle in EPTO mode, the service brake could be depressed andheld and the high beams flashed on and off twice. Once the service brakeis released subsequent activations of the high beams could generate asignal for toggling the traction motor's operation. In any event, whenthe traction motor is under the control of “chassis initiated” inputs.TEM input states are ignored or circumvented.

Turning now to FIG. 8, a hybrid-electric powertrain with a PTO drivenhydraulic system 800 is shown. The hybrid-electric powertrain with a PTOdriven hydraulic system 800 comprises an internal combustion engine 802,an electric motor and generator 803, a PTO 804, and a first hydraulicpump 806 and a second hydraulic pump 808. The PTO 804 is adapted toreceive power from either the internal combustion engine 802 or theelectric motor and generator 803. The PTO 804 drives the first hydraulicpump 804 and the second hydraulic pump 808.

As shown in FIG. 8, the first hydraulic pump 806 is a fixed displacementhydraulic pump, such as a vane pump, while the second hydraulic pump 808is a variable displacement hydraulic pump, such as a piston pump.

The second hydraulic pump 808 has a control motor 810 and/or a controlsolenoid 812 to control the adjustment of the variable displacementsetting of the second hydraulic pump 808. The control motor 810 may be aan electric motor, an electro-magnet stepper motor, or the like. Thecontrol solenoid 812 may be a an electro-magnetic solenoid device or thelike.

It is contemplated that the internal combustion engine 802 may beutilized to drive the PTO 804 to power the first hydraulic pump 806,while the electric motor and generator 803 is typically utilized topower the second hydraulic pump 808. The use of the first hydraulic pump806 or the second hydraulic pump 808 often depends on a load levelplaced on a hydraulic system 805. A large hydraulic load will utilizethe first hydraulic pump 806 driven by the internal combustion engine802, while a small hydraulic load will utilize the second hydraulic pump808 driven by the electric motor and generator 803.

The internal combustion engine is adapted to supply torque to thehydraulic pumps 806, 808 at engine speeds from about 700 RPM to about2000 RPM. However, the electric motor and generator 803 produces a hightorque level at operating speeds of less than about 1500 RPM. Therefore,when the electric motor and generator 803 is being utilized to run thesecond hydraulic pump 808 via the PTO 804, displacement of the secondhydraulic pump is adjusted to a larger displacement if the hydraulicload on the hydraulic system 805 requires the electric motor andgenerator 803 to operate at a speed above 1500 RPM. The control motor810 and/or the control solenoid 812 increase the displacement of thesecond pump 808 such that electric motor and generator 803 may supplysufficient hydraulic fluid flow and pressure to the hydraulic system805, while also operating at a speed of less than 1500 RPM.

Similarly, if the load within the hydraulic system 805 decreases, thedisplacement of the second hydraulic pump 808 may be adjusted to asmaller displacement, and the electric motor and generator 803 may beslowed to an speed below 1500 RPM.

In addition to adjusting the displacement of the second hydraulic pump808 when the load of the hydraulic system 805 changes to a load thatrequires the electric motor and generator to operate a speed above 1500RPM, it is also contemplated that the second hydraulic pump 808 may beadjusted by the control motor 810 and/or the control solenoid 812 to adisplacement that allows the electric motor and generator to operate ata higher level of efficiency. For example, if the electric motor andgenerator produces torque most efficiently at a speed of 1300 RPM, thedisplacement of the second hydraulic pump 808 may be adjusted so thatthe load of the hydraulic system 805 is met by the second hydraulic pump808, while the electric motor and generator is operating at the speed of1300 RPM.

The hydraulic system 805 depicted in FIG. 8 further comprises areservoir 814 that contains hydraulic fluid used in the hydraulic system805. The reservoir is in fluid communication with hydraulic motors 816,hydraulic cylinders 817, and hydraulic valves 818 of the hydraulicsystem, providing the necessary fluid to operate the hydraulic motors816, hydraulic cylinders 817, and hydraulic valves 818.

The electric motor and generator 803 is connected to a battery 820 andan electrical controller 822. The battery 820 stores electrical powerfor use by the electric motor and generator 803. The electricalcontroller 822 regulates electrical energy between the battery 820 andthe electrical motor and generator 803.

Turning now to FIG. 9, a specific control arrangement and networkarchitecture 900 on which the hybrid-electric powertrain with a PTOdriven hydraulic system 800 state may be implemented. A first remotethrottle 902 and/or a second remote throttle 904 are provided on TEMcomponents to give a user the ability to control the output of theelectric motor and generator 803 or the internal combustion engine 802in order to control the hydraulic system 805. The first remote throttle902 is a variable pedal throttle, while the second remote throttle 904is a hand operated vernier throttle.

As shown in FIG. 9, the first remote throttle is electrically connectedto the Engine Control Module, or Electronic Control Module, (“ECM”) 906.The second remote throttle 904 may be electrically connected to the ECM906 via a remote engine speed control module (“RESCM”) 908 or a remotepower module 910. The RESCM 908 and the remote power module 910 areelectronically connected to an Electronic System Controller (“ESC”) 912via a J1939 compliant cable 914.

The ESC 912 is electronically connected to the ECM 906 via a J1939compliant cable 916. The J1939 compliant cable 916 additionally connectsa gauge cluster 918, a hybrid control module 920, and a transmissioncontrol module 922 to the ECM 906. The ESC 912 monitors the internalcombustion engine 802 and the electric motor and generator 803 as wellas the demand of the hydraulic system 805 and input from the firstremote throttle 904 and/or the second remote throttle 906, and generatescontrol signals adapted to control the internal combustion engine 802and the electric motor and generator 803. The demand of the hydraulicsystem 805 is greatly influenced by the input from the first remotethrottle 904 and/or the second remote throttle 906.

The ESC 912 will generate speed commands for the internal combustionengine 802 and/or the electric motor and generator 803 such that thefirst hydraulic pump 804 and/or the second hydraulic pump 806 fulfillthe demand of the hydraulic system 805. For instance, the ESC 912 maygenerate a signal that increases or decreases the speed of the electricmotor and generator 803 in order to provide sufficient hydraulic fluidflow from the second hydraulic pump 806. Similarly, the ESC 912 maygenerate a signal that increases or decreases the speed of the internalcombustion engine 802 in order to provide sufficient hydraulic fluidflow from the first hydraulic pump 804.

The ESC 912 additionally generates an output signal that is transmittedto the second hydraulic pump 806 in the event the displacement of thesecond hydraulic pump 806 is to be modified. If a hydraulic load isabove a predetermined threshold, the displacement of the secondhydraulic pump 806 maybe For instance, if the electric motor andgenerator 803 is being used to power the second hydraulic pump, and thespeed of the electric motor and generator 803 is approaching 2000 RPM,the ESC 912 generates an output signal that causes the control motor 810or the control solenoid 812 to increase the displacement of the secondhydraulic pump 806, such that the output of the second hydraulic pump806 is increased, and the speed of the electric motor and generator 803is maintained in a proper operating range.

It is additionally contemplated that both the first hydraulic pump 804and the second hydraulic pump 806 may be used simultaneously. In such aconfiguration the ESC 912 generates an output signal to the controlmotor 810 or the control solenoid 812 in order to vary the displacementof the second hydraulic pump 806. In such a configuration, a smallerfirst hydraulic pump 804 may be utilized, as the second hydraulic pump806 will provide additionally pumping capacity to satisfy the demands ofthe hydraulic system 805.

The hydraulic system 805 of the present embodiment may be utilized topower variable speed applications, such as digger derricks, pressurediggers, document shredders, and other variable speed devices.

Additionally, the use of the a variable displacement second hydraulicpump 806 enhances energy utilization by the hybrid-electric powertrainwith a PTO driven hydraulic system 800, as the engine 802 and/or theelectric motor and generator 803 may be operated at more efficientsettings. Therefore, fuel usage, or electric power required, will belowered.

Turning next to FIG. 10 a hydraulic hybrid powertrain 1000. Thehydraulic hybrid powertrain 1000 comprises an internal combustion engine1002 a hydraulic pump 1004 connected to and driven by a PTO 1003. ThePTO may be powered by the internal combustion engine 1002, or may be aPTO has described above that may be powered by an electric motor andgenerator 1005 and/or the internal combustion engine 1002.

The hydraulic hybrid powertrain 1000 additionally comprises a hydraulicaccumulator 1006 disposed in fluid communication with the hydraulic pump1004.

The hydraulic accumulator 1006 is adapted to store pressurized hydraulicfluid from the hydraulic pump 1004. A hydraulic reservoir 1007additionally is provided in fluid communication with the hydraulic pump1004. The hydraulic reservoir 1007 stores low pressure hydraulic fluidthat may be pressurized by the hydraulic pump 1004.

An accumulator isolation valve 1008 is disposed at an outlet of thehydraulic accumulator 1006. The accumulator isolation valve 1008controls the flow of hydraulic fluid from the hydraulic accumulator1006. An accumulator solenoid 1010 positions the accumulator isolationvalve 1008 between at least a first position that allows hydraulic fluidto flow from the hydraulic accumulator 1006 and a second position thatprevents hydraulic fluid from flowing from the hydraulic accumulator1006. It is contemplated that the accumulator solenoid 1010 may alsoposition the accumulator isolation valve 1008 at a variety ofintermediate positions between the first position and the secondposition to control the flow of hydraulic fluid from the hydraulicaccumulator 1006.

An accumulator transducer 1012 is disposed in fluid communication withthe hydraulic accumulator 1006. The accumulator transducer 1012 providesan output signal to monitor the pressure within the hydraulicaccumulator 1012. The accumulator transducer 1012 may be utilized tocontrol operation of the hydraulic pump 1004 such that pressure withinthe hydraulic accumulator 1006 may be maintained at operating levels,yet the hydraulic pump 1004 may only be operated intermittently.

The hydraulic hybrid powertrain 1000 additionally comprises vehiclehydraulic system 1013. The vehicle hydraulic system 1013 may comprise anopen center hydraulic system 1015 a, a closed center hydraulic system1015 b, or both the open center hydraulic system 1015 a, and the closedcenter hydraulic system 1015 b.

The vehicle hydraulic system 1013 comprises a vehicle hydrauliccomponent transducer 1014. The vehicle hydraulic component transducer1014 generates an output signal in response to a hydraulic load withinthe vehicle hydraulic system. The vehicle hydraulic component transducer1014 is in electrical communication with an ESC 1016. The ESC 1016 is inelectrical communication with a RPM 1018, an ECM 1024, an operatordisplay 1026, and a gauge cluster 1028.

The ESC 1016 monitors the output of the hydraulic component transducer1014 and causes the RPM 1018 to generate an output signal 1022 that istransmitted to the accumulator solenoid 1010 to position the accumulatorisolation valve 1008. The RPM 1018 additionally is adapted to receiveinput signals 1020 from vehicle hydraulic system 1013 indicating thatthe vehicle hydraulic system 1013 has been activated. The RPM 1018 maythus generate the output signal 1022 that is transmitted to theaccumulator solenoid 101 to position the accumulator isolation valve1008. It is contemplated that the input signals 1020 from the vehiclehydraulic system 1013 may be utilized generate the output signal 1022 tocontrol an initial opening of the accumulator isolation valve 1008. Itis contemplated that the input signals from the vehicle hydrauliccomponent transducer 1014 may be utilized to generate the output signal1022 to control the closing of the accumulator isolation valve 1008 whenno hydraulic load is present within the vehicle hydraulic system 1013.

The ESC 1016 may also be utilized to reduce the speed of the internalcombustion engine 1002, or even shut off the engine 1002, when nohydraulic load is present within the vehicle hydraulic system 1013, bycommunicating with the ECM 1024. Similarly, the ESC 1016 may be utilizedto increase the speed of the internal combustion engine 1002 via the ECM1024 if the load present within the vehicle hydraulic system 1013 is notbeing met by the hydraulic pressure within the hydraulic accumulator1006 and the hydraulic pump 1004 is required to raise the pressure within the hydraulic accumulator 1006.

The accumulator transducer 1012 may be used to generate a message on theoperator display 1026, or cause an indication on the gauge cluster 1028,such that an operator may know the state of the hydraulic accumulator1006.

The accumulator isolation valve 1008 reduces internal parasitic leakagewithin the vehicle hydraulic system 1013 by preventing hydraulic fluidfrom the hydraulic accumulator 1006 to flow past the closed accumulatorisolation valve 1008.

1. A vehicle equipped for power take off operation using directapplication of power from a hybrid electric powertrain comprising: acontroller area network and body computer connected to receive aplurality of chassis input signals; a data link based remote powermodule installed on the vehicle for generating body demand signals forinitiating operation of the vehicle hybrid electric powertrain for apower take off operation; and an execution module stored on a memory ofthe a body computer for execution by the body computer responsive toselected chassis input signals for generating control signals for thehybrid electric powertrain for the power take off operation.
 2. Thevehicle equipped for power take off operation using direct applicationof power from a hybrid electric powertrain of claim 1, wherein thehybrid electric powertrain comprises an internal combustion engine andan electric motor and generator, and wherein at least one of theinternal combustion engine and the electric motor and generator suppliestorque for the power take off operation.
 3. The vehicle equipped forpower take off operation using direct application of power from a hybridelectric powertrain of claim 2, wherein the vehicle is a parallel typehybrid electric powertrain having the internal combustion engineconnected to the electric motor and generator to allow operation of theelectric motor and generator as a generator concurrently with operationof the power take off operation directly from the internal combustionengine.
 4. The vehicle equipped for power take off operation usingdirect application of power from a hybrid electric powertrain of claim3, wherein the programming gives priority to the plurality of chassisinput signals over the body demand signals.
 5. The vehicle equipped forpower take off operation using direct application of power from a hybridelectric powertrain of claim 4, wherein sources for the plurality ofchassis input signals are selected from existing controls of thevehicle.
 6. The vehicle equipped for power take off operation usingdirect application of power from a hybrid electric powertrain of claim4, further comprising a dedicated switch providing the plurality ofchassis input signals.
 7. A vehicle equipped for power take offoperation using direct application of power from a hybrid electricpowertrain, comprising: means responsive to a plurality of chassis inputsignals for generating a chassis demand signal for initiating operationof the hybrid electric powertrain to support power take off operation;and means responsive to operator inputs and installed on the vehicle forgenerating body demand signals for initiating operation of the hybridelectric powertrain to support power take off operation.
 8. The vehicleequipped for power take off operation using direct application of powerfrom a hybrid electric powertrain as set forth in claim 7, wherein thehybrid electric powertrain comprises an internal combustion engine andan electric motor and generator, and wherein at least one of theinternal combustion engine and the electric motor and generator suppliestorque for the power take off operation.
 9. The vehicle equipped forpower take off operation using direct application of power from a hybridelectric powertrain as set forth in claim 8, wherein the vehicle is aparallel type hybrid electric powertrain having the internal combustionengine connected to the electric motor and generator to allow operationof the electric motor and generator as a generator concurrently withoperation of the power take off operation directly from the internalcombustion engine.
 10. The vehicle equipped for power take off operationusing direct application of power from a hybrid electric powertrain asset forth in claim 9, wherein the means responsive to operator inputscomprises programming for execution by a body computer.
 11. The vehicleequipped for power take off operation using direct application of powerfrom a hybrid electric powertrain as set forth in claim 10, wherein theprogramming gives priority to the plurality of chassis input signalsover the body demand signals.
 12. The vehicle equipped for power takeoff operation using direct application of power from a hybrid electricpowertrain as set forth in claim 11, wherein sources for the pluralityof chassis input signals are selected from existing controls of thevehicle.
 13. A vehicle comprising: an internal combustion engine and anelectric motor and generator connectable using an autoclutch to allowparallel operation for power take off operation; a body computerconnected to receive a plurality of chassis inputs and responsive to theplurality of chassis inputs operational to process programming usingvalues for the plurality of chassis inputs to generate control signals;a data link based module installed on the vehicle through which inputscan be entered by an operator to initiate operation of the power takeoff operation using either the internal combustion engine or theelectric motor and generator; and an execution module stored on memoryin the body computer for execution on the body computer for overridinginputs to the data link based module with the plurality of chassisinputs for initiating operation of at least one of the internalcombustion engine and the electric motor and generator for power takeoff operation.
 14. The vehicle of claim 13, wherein the vehicle is aparallel type hybrid electric powertrain having the internal combustionengine connected to the electric motor and generator to allow operationof the electric motor and generator as a generator concurrently withoperation of the power take off operation directly from the internalcombustion engine.
 15. The vehicle of claim 13 further comprising adedicated switch providing the plurality of chassis input signals. 16.The vehicle of claim 13, wherein the plurality of chassis inputs aregenerated from existing controls of the vehicle.
 17. The vehicle ofclaim 16, wherein the plurality of chassis inputs are generated fromheadlamp control.
 18. The vehicle of claim 13 further comprising adedicated switch providing the plurality of chassis inputs.
 19. Thevehicle of claim 13, wherein the internal combustion engine is a dieselengine.
 20. The vehicle of claim 13, wherein the power take offoperation comprises an aerial lift.